The study sample included 126 individuals with traumatic brain injury in 17 states. The sample was representative of TBI demographics for gender, ethnicity, and socioeconomic status.

The RIPA-2 scores distinguish dramatically between groups known to have cognitive deficits and those known to have normal cognitive skills. The investigations were done by independent researchers working in hospitals, rehabilitation centers, clinics, and private practices. Convincing evidence also is provided to demonstrate that RIPA-2 items are not biased with regard to age or gender.